Hospital Acquired Pressure Ulcers (HAPUs) are damages caused to skin and its underlying tissues due to prolonged pressure applied on the skin. Traditionally, turn protocols (repositioning patients at regular intervals) are utilised to reduce the incidence of pressure ulcers. But adherence to turn protocols is particularly challenging for nursing teams, given the high number of interventions in ICU, and lack of widely available tools to monitor patient’s position and generate alerts. To overcome this problem, working together with intensivists, we developed a novel continuous patient position and posture monitoring system named PRESENSE.

The PRESENSE uses an ultra-low power wearable device attached to the patient’s chest to capture the patient’s position and posture. The wearable device uses an Inertial Measurement Unit (IMU) with sensor fusion algorithms to represent the orientation of the patient’s torso with respect to the patient bed to compute position and posture. This data is continuously transmitted from the wearable device and received wirelessly by a gateway device (Android-based tablet). The gateway device concurrently pushes the position data to the cloud and alerts the nurses visually via the screen display according to the standardized turn protocol. With cloud enablement, doctors and hospital administrators can remotely access the data using a cloud-based web application.

Further, PRESENSE functionality was extended to measure the patient’s head up angle (elevation of the head of the bed). Maintaining the head up angle at 30-45 degrees is known to reduce a type of commonly occurring lung infection in ventilated patients called Ventilator Associated Pneumonia (VAP). When non-compliant with the prescribed head up angle values, PRESENSE will raise alerts helping nurses to comply with the protocol.

PRESENSE system was initially validated in a laboratory setting for its functionality, reliability and accuracy. Sensor orientation result obtained from the PRESENSE system had excellent correlation with the standard angular reference system with a maximum deviation of ±1°. The system was also successfully able to raise alerts when non-compliant with the protocols. To assess the efficacy of the system to improve turn protocol compliance in a clinical setting, an IRB approved multi-phase, multicentre, non-randomized clinical trial was conducted. Over 1450 hours of patient data were collected from over 40 ICU patients. Clinical trial results proved that a statistically significant difference in average turn protocol compliance exists in the intervention group (80.15 %) compared to the control group (24.36 %), thereby ascertaining that with use of PRESENSE, nurses could better comply with the turn protocol. Nurses found the system to be more effective and easier to use compared to manual reminders with most having the intention to use the system.